Interest in assistive and autonomous techniques for passenger vehicles is increasing rapidly; the benefits of partial autonomy are both numerous and profound. In a traditional automotive vehicle, when steering an automobile, a driver has to continuously adjust the steering direction. Some of those adjustments implement discrete choices, such as the choice to change lanes on a highway, or the choice to turn at an intersection. Other adjustments arise from the curvature of the road, or from the vehicle dynamics. For example, on a curved road a driver would drive off the road without adjustment of the steering wheel. Thus, even when staying in the same lane, drivers have to constantly change the angle of the steering wheel to stay in their lane. The constant need to adjust the steering direction causes a burden on drivers often resulting in fatigue. Failure to provide this constant adjustment results in unintended lane departures, which is one of the primary causes of accidents on highways.
Active steering assistance systems that automatically adjust the steering angle to follow the road can make it difficult for the driver to correct the vehicle's position. For example, the steering wheel may turn independent from the driver. Furthermore, the detection of lane markings, optically or otherwise, is sometimes infeasible.
Lane Departure Systems that merely provide warning signals allow the driver to maintain control; however, such systems require a high level of driver responsibility to steer the vehicle. That is, simply alerting a driver to the possibility of a lane change does not assist the physical steering.